JP2009187440A - Observation image correction device, observation image correction program, and observation image correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an accurate ortho-image to be generated through ortho-correction of an observation image without performing a work for manually setting position information. <P>SOLUTION: A simulation image generation section 110 generates a simulation intensity image 171 and simulation image coordinate data 172 based on observation condition information 192 and a digital elevation model (DEM) 181. An agreement point detection section 120 detects a point of agreement 831 between an observation image 191 and the simulation intensity image 171. A latitude-longitude resampling section 130 affine transforms the observation image 191 so as to be superposed on the simulation intensity image 171 based on the point of agreement 831, specifies a pixel of the simulation intensity image 171 corresponding to a pixel of the observation image 191, acquires a coordinate corresponding to the observation image 191 from simulation image coordinate data 172, and generates observation image coordinate data 193. An ortho-correction section 140 ortho-corrects the observation image 191 based on the observation image coordinate data 193, and generates the ortho-image 196. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an observation image correction apparatus, an observation image correction program, and an observation image correction method for ortho-correcting a synthetic aperture radar image, for example.

  As typical methods for creating an orthocorrected image (ortho image) from an observation image (synthetic aperture radar image) obtained by a synthetic aperture radar, there are the following methods. An ortho image is an image corrected by orthographic projection as if viewed from directly above.

(1) The observation point of each pixel of the observation image is obtained in consideration of the altitude using orbit information, slant range, DEM (Digital Elevation Model), etc., and orthorectification is performed based on this.
(2) The position (latitude and longitude) of each pixel is manually input for several pixels on the observed image, and the geometric distortion is corrected by polynomial transformation based on the input value.
JP 2003-141507 A JP 2007-248216 A JP 2005-292882 A JP 2006-189372 A JP 2003-323611 A JP 2004-171413 A JP 2003-241653 A

The method (1) has the following problems.
(A) The observation image is not projected on the map, but the standard observation image sold is projected on the map. Note that the observation image of the product for sale is assumed to have an altitude of zero meters and is not an ortho image because the altitude is not considered. In addition, the observation image of the product for sale does not match the actual topography or road.
(B) If there is an error in the distance (slant range) and orientation from each pixel of the observation image to the observation satellite equipped with the synthetic aperture radar, the observation time of each observation value, or the orbit information of the observation satellite, the error is orthorectified. It becomes an image error, and the terrain, roads, buildings, etc. shown by the ortho image do not match the actual ones. These information on recent observation satellites (for example, DAICHI [ALOS1]) and aircraft have good accuracy, but information on observation satellites and aircraft in the 1990s or older has large errors. For example, the orbit information of Fuyo 1 has an error of several hundred meters. For this reason, the method (1) is not suitable except for recently observed images.
(C) In order to perform ortho correction in consideration of errors included in various types of information to be used (for example, orbit information), it is necessary to manually set accurate position information for several pixels on the observed image. For accurate position information, a coordinate value of a ground control point (GCP) that is measured in advance with high accuracy is used.

The method (2) has the following problems.
(A) It is necessary to manually set accurate position information for several pixels on the observed image.
(B) The position is shifted except for several pixels (GCP) in which accurate position information is manually set.

  An object of the present invention is, for example, to make it possible to create an accurate ortho image by ortho-correcting an observation image without performing an operation of manually setting position information.

  An observation image correction apparatus according to the present invention includes an observation image storage unit that stores an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device, and observation conditions for the radar observation. Using the storage device, the observation condition storage unit that stores the observation condition information indicating the information on the plane, and the altitude data indicating the plane coordinates of each grid point on the ground surface and the altitude of each grid point using the storage device A radar processing based on the elevation data storage unit, the observation condition information stored in the observation condition storage unit, and the elevation data stored in the elevation data storage unit, the CPU (Central Processing Unit) Simulation image generation that generates a simulated image showing the surface image based on simulated data acquired by simulated radar observation A plurality of pixels constituting the observation image stored in the observation image storage unit and a plurality of pixels constituting the simulation image generated by the simulation image generation unit using a CPU, The simulated image generated by the simulated image generation unit based on the elevation data stored in the elevation data storage unit and the corresponding pixel identification unit that identifies the pixel of the simulated image corresponding to the pixel of the observation image A simulated image coordinate data generating unit that generates, using a CPU, simulated image coordinate data indicating planar coordinates corresponding to the pixel of the pixel, and a pixel of the simulated image corresponding to the pixel of the observed image specified by the corresponding pixel specifying unit And the plane image corresponding to the pixel of the simulated image indicated by the simulated image coordinate data generated by the simulated image coordinate data generation unit. An observation image coordinate data generation unit that generates, using a CPU, observation image coordinate data indicating a plane coordinate corresponding to the pixel of the pixel, and a position in which the pixel of the observation image stored in the observation image storage unit corresponds to the plane coordinate A correction image generation unit that generates a correction image using a CPU based on the observation image coordinate data generated by the observation image coordinate data generation unit.

  In the observed image correction apparatus, the simulated image generating unit generates a fore-shortened image that is caused to fall down on an observation radar side that has performed a radar observation and viewed as a simulated image.

  In the observation image correction device, the simulated image generation unit calculates three-dimensional coordinates of an observation radar that has performed radar observation based on the observation condition information, and uses the calculated three-dimensional coordinates of the observation radar and the elevation data. The distance from the observation radar to each grid point on the ground surface and the electromagnetic wave emitted by the observation radar based on the plane coordinates of each grid point shown on the ground surface and the elevation of each grid point on the ground surface indicated by the elevation data The incident angle at each lattice point on the ground surface is calculated, the intensity of the reflected wave from each lattice point on the ground surface is calculated based on the calculated incident angle, and the position in the image corresponding to the calculated distance is calculated. The simulated image is generated by adding a shadow corresponding to the calculated intensity to a certain pixel.

  In the observed image correction device, the corresponding pixel specifying unit specifies two pixels of the simulated image corresponding to two pixels of the observed image, and each pixel position of the two pixels of the observed image and the simulated image A pixel of the simulated image that is at the same pixel position as the pixel of the observed image after affine transformation is obtained by affine transforming at least one of the observed image and the simulated image based on the amount of positional deviation from the pixel position of each of the two pixels As a pixel of the simulated image corresponding to the pixel of the observed image.

  In the observed image correction apparatus, the observed image is an optical image captured using an optical sensor.

  The observation image correction program of the present invention includes an observation image storage unit that stores an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device, and observation conditions for the radar observation. Using the storage device, the observation condition storage unit that stores the observation condition information indicating the information on the plane, and the altitude data indicating the plane coordinates of each grid point on the ground surface and the altitude of each grid point using the storage device Using the altitude data storage unit stored therein, the simulated image generation unit is configured to detect radar based on the observation condition information stored in the observation condition storage unit and the elevation data stored in the elevation data storage unit. Observation is simulated using a CPU (Central Processing Unit), and an image of the ground surface is shown based on simulated data acquired by simulated radar observation. A simulated image generation process for generating a simulated image, and a corresponding pixel specifying unit that includes a plurality of pixels constituting the observed image stored in the observed image storage unit and the simulated image generated by the simulated image generating unit. A plurality of constituent pixels are compared using a CPU, a corresponding pixel specifying process for specifying a pixel of the simulated image corresponding to a pixel of the observation image, and a simulated image coordinate data generation unit are stored in the elevation data storage unit. Simulated image coordinate data generation processing for generating, using a CPU, simulated image coordinate data indicating plane coordinates corresponding to pixels of the simulated image generated by the simulated image generation unit based on the stored elevation data; The observed image coordinate data generating unit includes the simulated image pixel corresponding to the pixel of the observed image specified by the corresponding pixel specifying unit and the simulated image coordinate data generating unit. Observation that uses the CPU to generate observation image coordinate data indicating the plane coordinates corresponding to the pixels of the observation image based on the plane coordinates corresponding to the pixels of the simulation image indicated by the simulation image coordinate data generated by the CPU The image coordinate data generation process and the corrected image generation unit generate an image in which pixels of the observation image stored in the observation image storage unit are arranged at positions corresponding to plane coordinates by the observation image coordinate data generation unit. Based on the observed image coordinate data, the computer is caused to execute a corrected image generation process that is generated using the CPU as a corrected image.

  In the observed image correction program, the simulated image generation unit generates, as the simulated image, a fore-shortened image that causes a high altitude to fall down on the observation radar side that performed radar observation.

  In the observation image correction program, the simulated image generation unit calculates three-dimensional coordinates of an observation radar that has performed radar observation based on the observation condition information, and uses the calculated three-dimensional coordinates of the observation radar and the elevation data. The distance from the observation radar to each grid point on the ground surface and the electromagnetic wave emitted by the observation radar based on the plane coordinates of each grid point shown on the ground surface and the elevation of each grid point on the ground surface indicated by the elevation data The incident angle at each lattice point on the ground surface is calculated, the intensity of the reflected wave from each lattice point on the ground surface is calculated based on the calculated incident angle, and the position in the image corresponding to the calculated distance is calculated. The simulated image is generated by adding a shadow corresponding to the calculated intensity to a certain pixel.

  In the observation image correction program, the corresponding pixel specifying unit specifies two pixels of the simulated image corresponding to two pixels of the observation image, and each pixel position of the two pixels of the observation image and the simulation image A pixel of the simulated image that is at the same pixel position as the pixel of the observed image after affine transformation is obtained by affine transforming at least one of the observed image and the simulated image based on the amount of positional deviation from the pixel position of each of the two pixels As a pixel of the simulated image corresponding to the pixel of the observed image.

  In the observed image correction program, the observed image is an optical image captured using an optical sensor.

  The observation image correction method of the present invention includes an observation image storage unit that stores an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device, and observation conditions for the radar observation. Using the storage device, the observation condition storage unit that stores the observation condition information indicating the information on the plane, and the altitude data indicating the plane coordinates of each grid point on the ground surface and the altitude of each grid point using the storage device Using the altitude data storage unit stored therein, the simulated image generation unit is configured to detect radar based on the observation condition information stored in the observation condition storage unit and the elevation data stored in the elevation data storage unit. A simulated image that simulates observation using a CPU (Central Processing Unit) and shows an image of the ground surface based on simulated data acquired by simulated radar observation A simulation image generation process for generating an image is performed, and the corresponding pixel specifying unit generates a plurality of pixels constituting the observation image stored in the observation image storage unit and the simulation image generated by the simulation image generation unit. A plurality of constituent pixels are compared using a CPU, a corresponding pixel specifying process for specifying a pixel of the simulated image corresponding to a pixel of the observed image is performed, and the simulated image coordinate data generation unit is the elevation data storage unit Simulated image coordinate data generation processing for generating simulated image coordinate data indicating plane coordinates corresponding to pixels of the simulated image generated by the simulated image generation unit based on the altitude data stored in the CPU using a CPU. And the observed image coordinate data generating unit includes the simulated image pixel and the simulated image coordinate data corresponding to the pixel of the observed image specified by the corresponding pixel specifying unit. The observed image coordinate data indicating the plane coordinates corresponding to the pixels of the observed image is generated using the CPU based on the plane coordinates corresponding to the pixels of the simulated image indicated by the simulated image coordinate data generated by the generator. The correction image generation unit generates an image in which the pixels of the observation image stored in the observation image storage unit are arranged at positions corresponding to the plane coordinates. Based on the observed image coordinate data generated by the unit, a correction image generation process is performed in which a correction image is generated using a CPU.

  According to the present invention, for example, it is possible to create an accurate ortho image (corrected image) by ortho-correcting an observation image without performing an operation of manually setting position information.

Embodiment 1 FIG.
First, radar observation, an observation image 191 obtained by radar observation, and an ortho image 196 created by the ortho correction device 100 according to Embodiment 1 by ortho correction (ortho vision correction) of the observation image 191 will be described.

1, 2 and 3 are diagrams showing radar observation.
In FIG. 1, an artificial satellite or an aircraft (hereinafter referred to as SAR 800) that carries SAR 800 (Synthetic Aperture Radar: Synthetic Aperture Radar) (observation radar) and observes the ground has a beam irradiation direction 803 directed obliquely downward from above. Is irradiated (emitted) with a beam 804 (electromagnetic wave, radio wave, microwave), and a backscattered wave 805 which is reflected and scattered back by the ground surface 823 is observed. The traveling direction 801 of the SAR 800 is referred to as “azimuth direction”, and the direction orthogonal to the traveling direction 801 is referred to as “range direction 802”. Since the SAR 800 performs observation by irradiating the beam 804 in the range direction 802 orthogonal to the traveling direction 801 instead of directly below, it is also referred to as a side-looking radar. A distance r between an antenna that irradiates the beam 804 and an object on the ground surface (hereinafter referred to as a terrestrial feature) from which the beam 804 is backscattered is referred to as a “slant range”.

  In FIG. 2, an observation image 191 is generated based on observation data obtained by radar observation, and represents the ground with the traveling direction 801 as the vertical direction and the beam irradiation direction 803 as the horizontal direction. However, the observed image 191 may include one in which the vertical and horizontal directions are interchanged, and another in which the definition of left and right and up and down is different. In FIG. 2, the observed image 191 is not projected on a map so that the orientation of the image indicates a specific orientation (for example, northward).

In the observed image 191, the position of the pixel is specified corresponding to the slant range r calculated based on the time from the irradiation of the beam 804 to the observation of the backscattered wave 805 with respect to the observed backscattered wave 805. The displayed pixels are displayed with lightness according to the intensity of the backscattered wave 805, and thus the ground image is formed.
The relationship between the slant range r and the pixel position is expressed by Equation 1 below.

r = r ₀ + n × (C / fAD) / 2 Formula 1
here,
“R ₀ ” is the slant range corresponding to the leftmost pixels (0, 0), (0, 1),..., (0, y), and “n” is the horizontal pixel number (0, 1,. X), “C” is the speed of light, and “fAD” is the sampling frequency of the beam 804 (and the backscattered wave 805).
“C / fAD” indicates the round-trip propagation time of the beam 804 (propagation time of the beam 804 + propagation time of the backscattered wave 805). Is sought after.

In FIG. 3, the slant range r is shorter at a high altitude such as the summit (point A) or the roof of the building compared to the ground surface at an altitude of 0 m. For this reason, the backscattered wave 805 from a point with a high altitude is represented in the observation image 191 as having reflected on the ground surface near SAR800. For example, the summit (point A) is represented in the observed image 191 as if it is located at the ridge (point B) on the equidistant line 812 of the slant range r.
In this way, it is called “fore shortening” that a high altitude point appears to fall down to the SAR 800 side.

FIG. 4 is a diagram showing the observation image 191 and the ridge line 813 in the first embodiment.
FIG. 5 is a diagram showing an ortho image 196 and a ridge line 813 in the first embodiment.
4 and 5, the position of the correct ridge line 813 is indicated by a dotted line so as to be superimposed on the observation image 191 and the ortho image 196.
In FIG. 4, it can be seen that the observed image 191 is shifted from the ridge line 813 to the SAR 800 side by the foreshortening, and the ortho image 196 is aligned with the ridge line 813 in FIG.
The orthorectification apparatus 100 according to the first embodiment orthorectifies the fore-shortened observation image 191 obtained by radar observation as shown in FIG. 4, and accurately sees the ground from directly above as shown in FIG. The represented ortho image 196 is created.
Orthorectification means orthographic projection, and orthoimage 196 is also called orthographic projection image.

FIG. 6 is a functional configuration diagram of the orthorectifying apparatus 100 according to the first embodiment.
A functional configuration of the orthorectifying apparatus 100 according to the first embodiment will be described below with reference to FIG.

  The orthocorrection device 100 (observation image correction device) includes a simulated image generation unit 110, a coincidence point detection unit 120, a latitude / longitude resampling unit 130, an orthocorrection unit 140, a simulated image storage unit 170, a DEM storage unit 180, and an observation image. A storage unit 190 is provided.

  The observation image storage unit 190 (observation condition storage unit) stores an observation image 191 indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device. In addition to image data, the observation image 191 includes observation condition information 192 indicating information on observation conditions for radar observation. For example, the observation condition information 192 includes orbit information of the SAR 800, observation time, beam irradiation direction 803, map projection information (presence / absence of map projection, projection used for map projection, etc.).

  The DEM storage unit 180 (elevation data storage unit) uses a storage device to store a DEM 181 (Digital Elevation Model) (elevation data) indicating the plane coordinates of each grid point on the ground surface and the altitude of each grid point partitioned by a grid. Remember.

  Hereinafter, the plane coordinates indicate two-dimensional coordinates of latitude and longitude. However, the plane coordinates may be expressed in a coordinate system other than the latitude / longitude coordinate system.

The simulated image generation unit 110 simulates radar observation using a CPU (Central Processing Unit) based on the observation condition information 192 stored in the observation image storage unit 190 and the DEM 181 stored in the DEM storage unit 180. Based on the simulated data acquired by the simulated radar observation, a simulated intensity image 171 (simulated image) indicating the image of the ground surface is generated. At this time, the simulated image generation unit 110 generates, as a simulated intensity image 171, a fore-shortened image that is shown by being brought down to the SAR 800 (observation radar) side where radar observation was performed at a high altitude. For example, the simulated image generation unit 110 calculates the three-dimensional coordinates of the SAR 800 based on the observation condition information 192, and based on the calculated three-dimensional coordinates of the SAR 800 and the DEM 181, the distance from the SAR 800 to each lattice point on the ground surface and the SAR 800. The incident angle at each lattice point on the ground surface formed by the beam 804 emitted by the above is calculated, and based on the calculated incident angle, the intensity of the backscattered wave 805 (reflected wave) from each lattice point on the ground surface is calculated and calculated. A simulated intensity image 171 is generated by adding a shadow corresponding to the calculated intensity to the pixel at the position in the image corresponding to the distance.
Further, the simulated image generation unit 110 (simulated image coordinate data generation unit) generates simulated image coordinate data 172 indicating the plane coordinates corresponding to each pixel of the simulated intensity image 171 based on the DEM 181 stored in the DEM storage unit 180. Generated using CPU. The simulated image coordinate data 172 includes simulated image latitude data 173 indicating the latitude corresponding to each pixel of the simulated intensity image 171 and simulated image longitude data 174 indicating the longitude corresponding to each pixel of the simulated intensity image 171.

  The simulated image storage unit 170 stores the simulated intensity image 171 and the simulated image coordinate data 172 generated by the simulated image generation unit 110 using a storage device.

  The coincidence point detecting unit 120 (corresponding pixel specifying unit) includes a plurality of pixels constituting the observed image 191 stored in the observed image storage unit 190 and a plurality of simulated intensity images 171 generated by the simulated image generating unit 110. These pixels are compared using the CPU, and the corresponding pixels in the observed image 191 and the simulated intensity image 171 are specified as the coincidence point 831.

The latitude / longitude resampling unit 130 (corresponding pixel specifying unit) specifies the pixel of the simulated intensity image 171 corresponding to the pixel of the observation image 191 based on the matching point 831 specified by the matching point detection unit 120 using the CPU. To do. For example, the latitude / longitude resampling unit 130 specifies two pixels of the simulated intensity image 171 corresponding to two pixels of the observed image 191, and each of the two pixel positions of the two pixels of the observed image 191 and each of the two pixels of the simulated intensity image 171. At least one of the observation image 191 and the simulated intensity image 171 is affine-transformed based on the amount of positional deviation from the pixel position of the pixel, and the pixel of the simulated intensity image 171 at the same pixel position as the pixel of the observation image 191 after affine transformation is obtained. It is obtained as a pixel of the simulated intensity image 171 corresponding to the pixel of the observed image 191.
Further, the latitude / longitude resampling unit 130 (observation image coordinate data generation unit) generates simulated image coordinate data 172 generated by the simulated image generation unit 110 and the pixels of the simulated intensity image 171 corresponding to the identified pixels of the observed image 191. Based on the above, observation image coordinate data 193 indicating plane coordinates corresponding to each pixel of the observation image 191 is generated using the CPU. The observation image coordinate data 193 includes observation image latitude data 194 indicating the latitude corresponding to each pixel of the observation image 191 and observation image longitude data 195 indicating the longitude corresponding to each pixel of the observation image 191.

  The ortho correction unit 140 (corrected image generation unit) uses the CPU to set each pixel of the observation image 191 to a pixel position corresponding to the plane coordinate based on the observation image coordinate data 193 generated by the latitude / longitude resampling unit 130. The ortho image 196 (corrected image) is generated by arranging.

FIG. 7 is a diagram illustrating an example of an appearance of the orthorectifying apparatus 100 according to the first embodiment.
In FIG. 7, an orthorectifier 100 includes a system unit 910, a display device 901 having a CRT (Cathode / Ray / Tube) or LCD (liquid crystal) display screen, a keyboard 902 (Key / Board: K / B), and a mouse 903. , FDD904 (Flexible / Disk / Drive), CDD905 (compact disc device), printer device 906, scanner device 907, and the like, which are connected by cables and signal lines.
The system unit 910 is a computer and is connected to the facsimile machine 932 and the telephone 931 with a cable, and is connected to the Internet 940 via a LAN 942 (local area network) and a gateway 941.

FIG. 8 is a diagram illustrating an example of hardware resources of the orthorectifying apparatus 100 according to the first embodiment.
In FIG. 8, the orthorectifying apparatus 100 includes a CPU 911 (also referred to as a central processing unit, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor) that executes a program. The CPU 911 is connected to the ROM 913, the RAM 914, the communication board 915, the display device 901, the keyboard 902, the mouse 903, the FDD 904, the CDD 905, the printer device 906, the scanner device 907, and the magnetic disk device 920 via the bus 912, and the hardware. Control the device. Instead of the magnetic disk device 920, a storage device such as an optical disk device or a memory card read / write device may be used.
The RAM 914 is an example of a volatile memory. The storage media of the ROM 913, the FDD 904, the CDD 905, and the magnetic disk device 920 are an example of a nonvolatile memory. These are examples of a storage device, a storage device, or a storage unit. A storage device in which input data is stored is an example of an input device, an input device, or an input unit, and a storage device in which output data is stored is an example of an output device, an output device, or an output unit.
The communication board 915, the keyboard 902, the scanner device 907, the FDD 904, and the like are examples of an input device, an input device, or an input unit.
The communication board 915, the display device 901, the printer device 906, and the like are examples of output devices, output devices, or output units.

  The communication board 915 is connected to the facsimile machine 932, the telephone 931, the LAN 942, and the like. The communication board 915 is not limited to the LAN 942 and may be connected to the Internet 940, a WAN (wide area network) such as ISDN, or the like. When connected to a WAN such as the Internet 940 or ISDN, the gateway 941 is unnecessary.

  The magnetic disk device 920 stores an OS 921 (operating system), a window system 922, a program group 923, and a file group 924. The programs in the program group 923 are executed by the CPU 911, the OS 921, and the window system 922.

  The program group 923 stores a program for executing a function described as “˜unit” in the embodiment. The program is read and executed by the CPU 911.

In the file group 924, in the embodiment, result data such as “determination result”, “calculation result of”, “processing result of” when executing the function of “to part”, “to part” The data to be passed between programs that execute the function “,” other information, data, signal values, variable values, and parameters are stored as items “˜file” and “˜database”. The observed image 191, the DEM 181, the simulated intensity image 171, the simulated image coordinate data 172, the coincidence point 831, the observed image coordinate data 193, the ortho image 196, and the like are examples of what is included in the file group 924. The observation image 191 and the DEM 181 are received by the communication board 915 via the network, or read from the stored storage medium by the FDD 904, the CDD 905, or the like, and stored in the keyboard 902 as the file group 924.
The “˜file” and “˜database” are stored in a recording medium such as a disk or a memory. Information, data, signal values, variable values, and parameters stored in a storage medium such as a disk or memory are read out to the main memory or cache memory by the CPU 911 via a read / write circuit, and extracted, searched, referenced, compared, and calculated. Used for CPU operations such as calculation, processing, output, printing, and display. Information, data, signal values, variable values, and parameters are temporarily stored in the main memory, cache memory, and buffer memory during the CPU operations of extraction, search, reference, comparison, operation, calculation, processing, output, printing, and display. Is remembered.
In addition, arrows in the flowcharts described in the embodiments mainly indicate input / output of data and signals. The data and signal values are the RAM 914 memory, the FDD 904 flexible disk, the CDD 905 compact disk, and the magnetic disk device 920 magnetic field. It is recorded on a recording medium such as a disc, other optical discs, mini discs, DVD (Digital Versatile Disc). Data and signal values are transmitted online via a bus 912, signal lines, cables, or other transmission media.

  In addition, what is described as “˜unit” in the embodiment may be “˜circuit”, “˜device”, “˜device”, and “˜step”, “˜procedure”, “˜”. Processing ". That is, what is described as “˜unit” may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented only by software, only hardware such as elements, devices, substrates, wirings, etc., or a combination of software and hardware, and further a combination of firmware. Firmware and software are stored as programs in a recording medium such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD. The program is read by the CPU 911 and executed by the CPU 911. That is, the program causes the computer to function as “to part”. Alternatively, the procedure or method of “to part” is executed by a computer.

FIG. 9 is a flowchart showing an ortho correction method according to the first embodiment.
The ortho correction method (observation image correction method) executed by the ortho correction device 100 according to Embodiment 1 will be described below with reference to FIG.
Each unit of the orthorectifying apparatus 100 executes each process described below using a CPU.

<S110: Observation condition information extraction process>
First, the simulated image generation unit 110 extracts observation condition information 192 from the observation image 191.
At this time, the simulated image generation unit 110 acquires the observation image 191 from the observation image storage unit 190 and extracts observation condition information 192 included in the observation image 191 from the acquired observation image 191. Observation condition information 192 includes orbit information of SAR 800, observation time, beam irradiation direction 803, map projection information (presence / absence of map projection, projection used for map projection, etc.), and the like.

<S120: Simulated Image Generation Processing>
Next, the simulated image generation unit 110 creates a simulated intensity image 171 based on the observation condition information 192 and the DEM 181.
At this time, the simulated image generation unit 110 acquires the DEM 181 from the DEM storage unit 180 and performs radar observation based on the observation condition information 192 extracted in the observation condition information extraction process (S110) and the DEM 181 acquired from the DEM storage unit 180. And a fore-shortened simulated intensity image 171 is created based on the simulated data acquired by the simulated radar observation. The created simulated intensity image 171 is shaded with brightness (luminance) corresponding to the intensity of the backscattered wave 805 observed by the SAR 800. The simulated image generation unit 110 stores the created simulated intensity image 171 in the simulated image storage unit 170.

FIG. 10 shows a simulated intensity image 179 that is not foreshortened, and FIG. 11 shows a simulated intensity image 171 that is foreshortened in the first embodiment.
The simulated image generation unit 110 foreshortens the simulated intensity image 179 (FIG. 10) generated from the DEM 181 when viewed from directly above by a radar observation simulation, and simulates the observed image 191. (FIG. 11) is created.
In the simulated intensity image 171 of FIG. 11, a point at a high altitude is seen falling down to the SAR 800 side. For example, the top of the mountain 811 displayed in FIG. 11 is closer to the SAR 800 side than in FIG.
In addition, in the simulated intensity image 171 of FIG. 11, a portion that is not shielded when viewed from the SAR 800 (a portion where the intensity of the backscattered wave 805 observed by the SAR 800 is strong) appears bright, and a portion that becomes a shadow when viewed from the SAR 800 (the SAR 800 The portion of the observed backscattered wave 805 having a low intensity) is shaded.

FIG. 12 is a flowchart showing the simulated image generation process (S120) of the first embodiment.
FIG. 13 is a relationship diagram between the point P and the observation point Q of the SAR 800 in the simulated image generation process (S120) of the first embodiment.
Details of the simulation image generation process (S120) will be described below with reference to FIGS.

<S121: Radar coordinate calculation processing>
In FIG. 12, the simulated image generation unit 110 calculates the three-dimensional coordinates of the point P where the SAR 800 was located at the observation time based on the orbit information of the SAR 800 and the observation time included in the observation condition information 192.

<S122: Slant range calculation process>
Next, the simulated image generation unit 110 acquires the DEM 181 from the DEM storage unit 180. The DEM 181 indicates the plane coordinates (latitude and longitude) of each grid point on the ground surface divided by the grid and the altitude of each grid point. That is, the DEM 181 indicates the three-dimensional coordinates (latitude, longitude, altitude) of each point on the ground surface. Then, the simulated image generation unit 110 uses the three-dimensional coordinates of the point P where the SAR 800 was located at the observation time calculated in the radar coordinate calculation process (S121) and each point on the ground surface indicated by the DEM 181 acquired from the DEM storage unit 180. The slant range r for a specific point on the surface of the earth (hereinafter referred to as an observation point Q) is calculated based on the three-dimensional coordinates. FIG. 13 shows the relationship between the point P and the observation point Q of the SAR 800. The simulated image generation unit 110 calculates the distance between the point P and the observation point Q of the SAR 800 as an estimated value of the slant range r with respect to the observation point Q calculated in the actual radar observation.

<S123: Pixel position specifying process>
Next, the simulated image generation unit 110 specifies the pixel position of the simulated intensity image 171 for displaying the observation point Q based on the slant range r calculated in the slant range calculation process (S122). The pixel position of the observation point Q is a pixel position that represents a point closer to the SAR 800 if the slant range r is shorter, and is a position that is farther from a pixel that represents a point closer to the SAR 800 as the slant range r is longer. In FIG. 13, the pixel position corresponding to the saddle point Q ′ near the SAR 800 on the equidistant line 812 having the same slant range r is specified for the observation point Q having a high altitude.

<S124: Incident angle calculation processing>
In addition, the simulated image generation unit 110 uses the incident angle θ of the beam 804 irradiated by the SAR 800 in the actual radar observation at the observation point Q based on the three-dimensional coordinates of the point P of the SAR 800 and the three-dimensional coordinates of the observation point Q. The estimated value of _inc is calculated.
As shown in FIG. 13, the incident angle θ _inc represents an angle formed by a line connecting the point P of the SAR 800 and the observation point Q (line-of-sight vector from the SAR 800 to the observation point Q) and the normal line 821. The normal line 821 indicates a line perpendicular to the tangent plane 822 that is in contact with the ground surface at the observation point Q.

<S125: reflected wave intensity calculation processing>
Next, the simulated image generation unit 110 estimates the intensity σ of the backscattered wave 805 from the observation point Q observed in the actual radar observation, based on the incident angle θ _inc calculated in the incident angle calculation process (S124). Calculate the value.

The intensity of the backscattered wave 805 is determined by the incident angle θ _inc and the substance constituting the surface of the observation point Q. Here, assuming that the ground surface is substantially uniformly composed of a uniform material such as soil, the intensity of the backscattered wave 805 is characterized by an incident angle θ _inc . The relationship between the incident angle θ _inc and the intensity of the backscattered wave 805 for various substances is described in several documents. For example, “HANDBOOK OF Radar Scattering Statistics for Terrain”, F.R. T.A. Ulaby, and M.M. C. In Dobson, Arttech House, 1989, the relational expression 2 between the incident angle θ _inc and the intensity σ of the backscattered wave 805 is given as follows.

σ [decibel] = P1 + {P2 × exp (−P3 × θ _inc )} + {P4 × cos ((P5 × θ _inc ) + P6)} Equation 2

  According to the document, the parameter values of the above equation 2 when the material constituting the ground surface is soil and rock (Soil and Rock) are “P1 = −85.984”, “P2 = 99”, “P3 = 0”. .628 ”,“ P4 = 8.189 ”,“ P5 = 3.414 ”, and“ P6 = −3.142 ”.

In Expression 2, the contribution of the incident angle θ _inc to the intensity σ of the backscattered wave 805 is indicated by the second term “exp (−P3 × θ _inc )”, and the intensity σ of the backscattered wave 805 is the incident angle θ. Decreases with increasing _inc . That is, in FIG. 13, when the tangent plane 822 of the observation point Q faces the SAR 800 side (incident angle θ _inc is small), the intensity σ of the backscattered wave 805 increases, and the tangent plane 822 of the observation point Q becomes SAR 800. When facing the opposite side (incident angle _θinc is large), the intensity σ of the backscattered wave 805 becomes small. For example, the intensity σ of the backscattered wave 805 from the slope before the mountain as viewed from the SAR 800 is large, and the intensity σ of the backscattered wave 805 from the slope on the opposite side of the mountain is small.

  In the radar coordinate calculation process (S121) to the reflected wave intensity calculation process (S125), the simulated image generation unit 110 targets a range wider than the ground surface represented by the observation image 191 and sets each point in the target range as the observation point Q. As described above, the pixel position corresponding to each observation point Q and the intensity σ of the backscattered wave 805 are calculated.

<S126: Simulated Strength Image Creation Processing>
Then, the simulated image generation unit 110 simulates the pixel specified by the pixel position specifying process (S123) with brightness (luminance) corresponding to the intensity σ of the backscattered wave 805 calculated by the reflected wave intensity calculation process (S125). An intensity image 171 is created. At this time, the simulated image generation unit 110 brightens the lightness as the intensity σ of the backscattered wave 805 increases, and darkens the lightness as the intensity σ of the backscattered wave 805 decreases.

FIG. 14 is a diagram showing an observation image 191 and a simulated intensity image 171 in the first embodiment.
Through the simulated image generation process (S120), the simulated image generation unit 110 can create a simulated intensity image 171 as if it were an actual observation image 191 as shown in FIG.

  Further, the simulated image generation unit 110 may set the intensity σ of the backscattered wave 805 in the sea portion to “0” regardless of the reflected wave intensity calculation process (S125). This is because most of the beam 804 is scattered on the opposite side of the SAR 800 due to specular reflection at the sea surface, and the intensity σ of the backscattered wave 805 observed by the SAR 800 is almost “0”. The DEM 181 published by the Geospatial Information Authority of Japan sets a specific value (−999) for the sea portion, so that discrimination between land and sea is easy.

  Returning to FIG. 9, the processing after the simulated image coordinate data generation processing (S130) of the ortho correction method will be described.

<S130: Simulated Image Coordinate Data Generation Processing>
The simulated image generation unit 110 creates simulated image coordinate data 172 corresponding to the simulated intensity image 171. The simulated image generation unit 110 stores the created simulated image coordinate data 172 in the simulated image storage unit 170.

FIG. 15 is a relationship diagram between the radar observation and the simulated intensity image 171 in the first embodiment.
FIG. 16 shows a simulated intensity image 171 and a conceptual diagram of simulated image coordinate data 172 in the first embodiment.
The simulated image coordinate data 172 created by the simulated image generation unit 110 in the simulated image coordinate data generation process (S130) will be described below with reference to FIGS.

In FIG. 15, observation points Q1, Q2 and Q3 having distances from the point P of the SAR 800 as R1, R2 and R3 (R1 <R2 <R3) in the left diagram are pixels Q1, Q2 and Q2 on the simulated intensity image 171, respectively. Corresponds to Q3. Since the simulated intensity image 171 is created based on the DEM 181 as described above, each pixel (eg, Q1, Q2, Q3) on the simulated intensity image 171 has known plane coordinates (latitude, longitude).
Therefore, the simulated image generation unit 110 can create simulated image coordinate data 172 indicating the plane coordinates corresponding to each pixel of the simulated intensity image 171 based on the DEM 181.

  For example, the simulated image generation unit 110 generates a two-dimensional array corresponding to each pixel of the simulated intensity image 171, sets the plane coordinates corresponding to each pixel in the two-dimensional array, and generates simulated image coordinate data 172. Hereinafter, the two-dimensional array in which “latitude” is set is referred to as simulated image latitude data 173, and the two-dimensional array in which “longitude” is set is referred to as simulated image longitude data 174.

In FIG. 16, the latitude and longitude corresponding to the pixel position (a, b) of the simulated intensity image 171 are the two-dimensional array element (a, b) of the simulated image latitude data 173 and the two-dimensional array of simulated image longitude data 174, respectively. Are indicated by elements (a, b).
In FIG. 16, each element of the two-dimensional array of the simulated image latitude data 173 is expanded on a two-dimensional plane, and an equal latitude line 173 a (lattice line) connecting elements having the same latitude is shown as a conceptual diagram of the simulated image latitude data 173. ing. Further, in FIG. 16, each element of the two-dimensional array of the simulated image longitude data 174 is expanded on a two-dimensional plane, and an equi-longitude line 174 a (meridian line, meridian) connecting elements having the same longitude is displayed in the simulated image longitude data 174. It is shown as a conceptual diagram.
Q1, Q2 and Q3 of the simulated image latitude data 173 indicate the latitudes of Q1, Q2 and Q3 of the simulated intensity image 171. Q1, Q2 and Q3 of the simulated image longitude data 174 are Q1, Q2 and Q3 of the simulated intensity image 171. Indicates longitude. In the simulated intensity image 171, Q2 representing the peak is displayed closer to the SAR 800 than the actual due to foreshortening, and therefore, the equilongitude line 174a of the simulated image longitude data 174 is distorted.

  Returning to FIG. 9, the processing after the map projection processing (S140) of the ortho correction method will be described.

<S140: Map projection processing>
The simulated image generation unit 110 projects the simulated intensity image 171 on the map according to the observed image 191.
At this time, the simulated image generation unit 110 determines whether or not the observation image 191 is projected on the map based on the map projection information included in the observation condition information 192. The map projection information indicates the presence / absence of map projection, map projection, and the like.
When it is determined that the observation image 191 is projected on the map, the simulated image generation unit 110 projects the simulated intensity image 171 generated in the simulated image generation process (S120) using the same projection as that of the observation image 191. Map projection is, for example, placing an image in a specific direction (for example, north). Examples of projections include Mercator projection, Mirror projection, Sanson projection, and Morweide projection.
When it is determined that the observation image 191 is not projected on the map, the simulated image generation unit 110 ends the map projection process (S140) without projecting the simulated intensity image 171 on the map.

<S150: Matching point detection process>
The coincidence point detection unit 120 detects a coincidence point 831 between the observed image 191 and the simulated intensity image 171.
At this time, the coincidence point detection unit 120 acquires the observation image 191 from the observation image storage unit 190 and also acquires the simulation intensity image 171 from the simulation image storage unit 170, and performs image matching between the observation image 191 and the simulation intensity image 171. Two or more coincidence points 831 (also referred to as tie points) between the observed image 191 and the simulated intensity image 171 are detected. However, the coincidence point 831 detected by the coincidence point detection unit 120 may be one point as described later. For example, the coincidence point detection unit 120 compares the brightness of each pixel of the observed image 191 with the brightness of each pixel of the simulated intensity image 171 by an area correlation method (an example of image matching), and compares the observed image 191 and the simulated intensity image 171. A matching point 831 is detected.

FIG. 17 is a diagram illustrating a detection result of the coincidence point 831 in the first embodiment.
For example, as a result of comparing the observed image 191 shown in FIG. 14 and the simulated intensity image 171 by the area correlation method, the pixels indicated by the crosses in the observed image 191 in FIG. It is.

<S160: Corresponding Pixel Identification Process>
The latitude / longitude resampling unit 130 affine-transforms the observed image 191 so as to overlap the simulated intensity image 171 based on the coincidence point 831, and specifies the pixel of the simulated intensity image 171 corresponding to the pixel of the observed image 191. Affine transformation means translation and rotation.

At this time, the latitude / longitude resampling unit 130 calculates the amount of deviation of the pixel position between the coincidence point 831 of the observation image 191 and the coincidence point 831 of the simulated intensity image 171 detected in the coincidence point detection process (S150) with the observation image 191. This is calculated as a deviation amount of the simulated intensity image 171. Although the simulated intensity image 171 is created based on the observation condition information 192, the simulated intensity image 171 and the observed image 191 are affected by an error of the observation condition information 192 (for example, an error of orbit information), an observation error of the SAR 800, and the like. There is a gap between the two. Therefore, the latitude / longitude resampling unit 130 calculates the amount of deviation between the observed image 191 and the simulated intensity image 171. Here, if at least one coincidence point 831 is detected, the shift amount in the parallel direction (vertical direction and horizontal direction) between the observed image 191 and the simulated intensity image 171 can be specified. Accordingly, the matching point 831 detected in the matching point detection process (S150) may be one point. If at least two coincidence points 831 are detected, it is possible to specify the amount of deviation between the observed image 191 and the simulated intensity image 171 in the parallel direction and the rotational direction. When the amount of deviation between the observed image 191 and the simulated intensity image 171 is different at each of the plurality of coincidence points 831, the latitude / longitude resampling unit 130 performs the least square method on the amount of deviation at each coincidence point 831, thereby observing the observed image 191. And the simulated intensity image 171 are specified.
Next, the latitude / longitude resampling unit 130 affine-transforms the observation image 191 according to the specified shift amount, and superimposes the coincidence point 831 of the observation image 191 on the coincidence point 831 of the simulated intensity image 171. However, the simulated intensity image 171 may be affine transformed to superimpose the observed image 191 and the simulated intensity image 171, or both the observed image 191 and the simulated intensity image 171 may be affine transformed to observe the observed image 191 and the simulated intensity. The image 171 may be superimposed. The coefficient of affine transformation is determined according to the amount of deviation between the observed image 191 and the simulated intensity image 171.
Then, the latitude / longitude resampling unit 130 identifies the pixel of the simulated intensity image 171 that overlaps the pixel of the observed image 191 as the pixel of the simulated intensity image 171 corresponding to the pixel of the observed image 191.

<S170: Observation Image Coordinate Data Generation Processing>
The latitude / longitude resampling unit 130 acquires the plane coordinates corresponding to each pixel of the observed image 191 from the simulated image coordinate data 172, and creates the observed image coordinate data 193. The observation image coordinate data 193 includes observation image latitude data 194 indicating the latitude corresponding to each pixel of the observation image 191 and observation image longitude data 195 indicating the longitude corresponding to each pixel of the observation image 191. Similar to the simulated image latitude data 173, the observed image latitude data 194 is obtained by setting “latitude” to each element of the two-dimensional array corresponding to each pixel of the observed image 191. Similarly to the simulated image longitude data 174, the observed image longitude data 195 is obtained by setting “longitude” in each element of the two-dimensional array corresponding to each pixel of the observed image 191. Creation of the observation image coordinate data 193 is referred to as resampling of latitude / longitude information of the observation image 191.

FIG. 18 is a relationship diagram between the simulated intensity image 171 and the observed image 191 and a relationship diagram between the simulated image coordinate data 172 and the observed image coordinate data 193 in the first embodiment.
In FIG. 18, the upper diagram shows a frame line of the observation image 191 that is affine-transformed by the corresponding pixel specifying process (S160) and overlaps the simulated intensity image 171. The lower left diagram shows a conceptual diagram of the observed image latitude data 194 created in the observed pixel coordinate data generation process (S170), and the lower right diagram shows the observed image longitude data 195 created in the observed image coordinate data generation process (S170). The conceptual diagram of is shown.

  In FIG. 18, for example, when the pixel (x1, y1) of the simulated intensity image 171 corresponds to the pixel (0, 0) of the observed image 191, the latitude / longitude resampling unit 130 stores the simulated image latitude data 173. The (x1, y1) th element is set as the (0, 0) th element of the observed image latitude data 194, and the (x1, y1) th element of the simulated image longitude data 174 is set to (0 , 0) set to the element.

  Returning to FIG. 9, the correction image generation processing (S180) of the ortho correction method will be described.

<S180: Corrected Image Generation Processing>
The ortho correction unit 140 performs ortho correction (ortho vision correction) on the observation image 191 based on the observation image coordinate data 193 to create an ortho image 196.
At this time, the orthocorrection unit 140 rearranges each pixel of the observation image 191 (for example, FIG. 4) at a pixel position corresponding to the plane coordinate indicated by the observation image coordinate data 193, and the observation image 191 is viewed from directly above. Orthorectify as shown. Then, the orthocorrection unit 140 stores the orthocorrected observation image 191 in the storage device as an orthoimage 196 (for example, FIG. 5) or prints it using the printer device 906. The rearrangement of each pixel of the observation image 191 is referred to as resampling of the observation image 191. When each pixel of the observation image 191 is resampled, blank pixels in which the pixels of the observation image 191 are not arranged are generated in the ortho image 196 due to the influence of foreshortening. Therefore, the ortho correction unit 140 interpolates blank pixels of the ortho image 196 based on surrounding pixels. For example, the ortho correction unit 140 uses linear interpolation, polynomial interpolation, cubic convolution, bilinear method (bilinear method), or the like as an interpolation method.

  The ortho correction method according to the first embodiment is an optimum method for a radar image (for example, a SAR image) obtained by radar observation. However, the ortho correction method in the first embodiment is also effective for observation images other than radar images. It is also effective for an optical image (an example of an observation image) captured by an optical sensor such as a camera. The optical sensor observes light (for example, sunlight) reflected from the ground surface. Since the optical image is greatly influenced by the constituents of the ground (such as soil and plants), it is difficult to create a simulated intensity image 171 that closely resembles the observed image 191 with only the incident angle and sun angle information. However, the simulated intensity image 171 can be made to resemble the observation image 191 sufficiently if it is a ground surface portion that can be regarded as almost one type of component such as a wilderness, desert, moon, or planet. . For this reason, the ortho correction in Embodiment 1 is applicable also to the observation image imaged with the optical and other sensors.

In the first embodiment, the orthorectifying apparatus 100 that orthorectifies an observation image in the following procedure has been described.
<Procedure 1> Extract trajectory information, observation start time (time corresponding to the head line of the image), and map projection information (presence of projection, projection, etc.) from the input image (observation image 191).
<Procedure 2> Latitude information (simulated image latitude data 173) and longitude information (simulated image longitude data 174) corresponding to each pixel of the simulated intensity image 171 and the simulated intensity image 171 are created using the DEM and the trajectory information. .
<Procedure 3> If the observed image 191 is projected on a map, the simulated intensity image 171 is projected on the map in accordance with the observed image 191.
<Procedure 4> The positional deviation between the simulated intensity image 171 and the observed image 191 is measured (a point that matches by image matching is automatically measured).
<Procedure 5> Latitude information (observation image latitude data 194) and longitude information (observation image longitude data 195) corresponding to each pixel of the observation image 191 are created based on the amount of deviation obtained by measurement (latitude). Information and longitude information resampling).
<Procedure 6> Based on the latitude information and longitude information obtained by resampling, the observation image 191 is orthorectified (resampling of the observation image 191).

The orthorectifying apparatus 100 described in the first embodiment has the following effects, for example.
(1) It is possible to create an accurate ortho image 196 by ortho-correcting the observed image 191 without manually setting the position information (GCP). That is, creation of the ortho image 196 can be automated.
(2) Since the observation condition information 192 (for example, orbit information) does not require high accuracy, the ortho image 196 can be created using the observation image 191 acquired in the past. Thereby, for example, the past terrain and the current terrain can be compared more accurately.
(3) Since the observation image 191 may or may not be projected on a map, an accurate ortho image 196 can be obtained using a standard product that is projected on a map.

The figure which shows radar observation. The figure which shows radar observation. The figure which shows radar observation. FIG. 5 shows an observation image 191 and a ridge line 813 according to Embodiment 1. FIG. 6 shows an ortho image 196 and a ridge line 813 according to Embodiment 1. FIG. 3 is a functional configuration diagram of the orthorectifying apparatus 100 according to the first embodiment. FIG. 3 is a diagram illustrating an example of an appearance of an orthorectifying apparatus 100 according to the first embodiment. FIG. 3 is a diagram illustrating an example of hardware resources of the orthorectifying apparatus 100 according to the first embodiment. 3 is a flowchart showing an ortho correction method according to the first embodiment. The figure which shows the simulation intensity | strength image 179 which is not foreshortening. FIG. 6 shows a simulated intensity image 171 subjected to fore-shortening in the first embodiment. 6 is a flowchart showing a simulated image generation process (S120) according to the first embodiment. FIG. 6 is a relationship diagram between a point P and an observation point Q of the SAR 800 in the simulated image generation process (S120) of the first embodiment. FIG. 6 shows an observation image 191 and a simulated intensity image 171 in the first embodiment. FIG. 6 is a relationship diagram between radar observation and simulated intensity image 171 in the first embodiment. FIG. 6 is a diagram showing a simulated intensity image 171 and a conceptual diagram of simulated image coordinate data 172 in the first embodiment. FIG. 6 shows a detection result of a coincidence point 831 in the first embodiment. FIG. 6 is a relationship diagram between a simulated intensity image 171 and an observed image 191 and a relationship diagram between the simulated image coordinate data 172 and the observed image coordinate data 193 in the first embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Orthogonal correction apparatus, 110 Simulated image production | generation part, 120 Matching point detection part, 130 Latitude / longitude resampling part, 140 Orthorectification part, 170 Simulated image storage part, 171 Simulated intensity image, 172 Simulated image coordinate data, 173 Simulated image Latitude data, 173a equal latitude line, 174 simulated image longitude data, 174a equal longitude line, 179 simulated intensity image, 180 DEM storage unit, 181 DEM, 190 observation image storage unit, 191 observation image, 192 observation condition information, 193 observation image Coordinate data, 194 observation image latitude data, 195 observation image longitude data, 196 ortho image, 800 SAR, 801 traveling direction, 802 range direction, 803 beam irradiation direction, 804 beam, 805 backscattered wave, 811 mountain, 812 equidistant line , 813 Ridge line, 8 1 normal line, 822 tangent plane, 823 ground surface, 831 coincidence point, 901 display device, 902 keyboard, 903 mouse, 904 FDD, 905 CDD, 906 printer device, 907 scanner device, 910 system unit, 911 CPU, 912 bus, 913 ROM, 914 RAM, 915 communication board, 920 magnetic disk device, 921 OS, 922 window system, 923 program group, 924 file group, 931 telephone, 932 facsimile machine, 940 Internet, 941 gateway, 942 LAN.

Claims (11)

An observation image storage unit for storing an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device;
An observation condition storage unit for storing observation condition information indicating information on observation conditions of the radar observation using a storage device;
An altitude data storage unit for storing altitude data indicating the plane coordinates of each grid point of the ground surface divided into grids and the altitude of each grid point using a storage device;
Based on the observation condition information stored in the observation condition storage unit and the elevation data stored in the elevation data storage unit, radar observation is simulated using a CPU (Central Processing Unit), and a simulated radar A simulated image generating unit that generates a simulated image indicating an image of the ground surface based on simulated data acquired by observation;
A plurality of pixels constituting the observation image stored in the observation image storage unit and a plurality of pixels constituting the simulation image generated by the simulation image generation unit are compared using a CPU, and the observation image is compared A corresponding pixel specifying unit for specifying the pixel of the simulated image corresponding to the pixel;
A simulated image that uses a CPU to generate simulated image coordinate data indicating planar coordinates corresponding to pixels of the simulated image generated by the simulated image generation unit based on the elevation data stored in the elevation data storage unit A coordinate data generation unit;
Corresponding to the pixels of the simulated image corresponding to the pixels of the observed image specified by the corresponding pixel specifying unit and the pixels of the simulated image indicated by the simulated image coordinate data generated by the simulated image coordinate data generating unit An observation image coordinate data generating unit that generates observation image coordinate data indicating a plane coordinate corresponding to a pixel of the observation image based on the plane coordinate using a CPU;
Based on the observation image coordinate data generated by the observation image coordinate data generation unit, an image in which pixels of the observation image stored in the observation image storage unit are arranged at positions corresponding to plane coordinates is used as a correction image. An observation image correction apparatus comprising: a correction image generation unit that generates using a CPU. 2. The observation according to claim 1, wherein the simulated image generation unit generates a fore-shortened image that causes a high altitude to fall down on an observation radar side that has performed radar observation and shows the simulated image as the simulated image. Image correction device. The simulated image generation unit calculates three-dimensional coordinates of an observation radar that has performed radar observation based on the observation condition information, and each lattice point of the ground surface indicated by the calculated three-dimensional coordinates of the observation radar and the elevation data The distance from the observation radar to each grid point on the ground surface based on the plane coordinates of the surface and the altitude of each grid point on the ground surface indicated by the elevation data and at each grid point on the ground surface formed by the electromagnetic wave emitted by the observation radar The incident angle is calculated, the intensity of the reflected wave from each lattice point on the ground surface is calculated based on the calculated incident angle, and the intensity calculated for the pixel at the position in the image corresponding to the calculated distance The observed image correction apparatus according to claim 1, wherein the simulated image is generated with a shadow corresponding to the image. The corresponding pixel specifying unit specifies two pixels of the simulated image corresponding to two pixels of the observation image, and each pixel position of the two pixels of the observation image and each pixel position of the two pixels of the simulation image At least one of the observed image and the simulated image is affine transformed based on the amount of misalignment, and the pixel of the simulated image at the same pixel position as the pixel of the observed image after affine transformation is converted to the pixel of the observed image. The observation image correction device according to claim 1, wherein the observation image correction device is obtained as a pixel of the simulated image corresponding to the image.   The observed image correction apparatus according to claim 1, wherein the observed image is an optical image captured using an optical sensor. An observation image storage unit for storing an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device;
An observation condition storage unit for storing observation condition information indicating information on observation conditions of the radar observation using a storage device;
Using an altitude data storage unit that stores altitude data indicating the plane coordinates of each grid point of the ground surface divided by a grid and the altitude of each grid point using a storage device,
A simulated image generation unit uses a CPU (Central Processing Unit) to perform radar observation based on the observation condition information stored in the observation condition storage unit and the elevation data stored in the elevation data storage unit. Simulated image generation processing for generating a simulated image indicating a ground image based on simulated data acquired by simulated radar observation;
The corresponding pixel specifying unit uses a CPU to generate a plurality of pixels constituting the observation image stored in the observation image storage unit and a plurality of pixels constituting the simulation image generated by the simulation image generation unit. And a corresponding pixel specifying process for specifying the pixel of the simulated image corresponding to the pixel of the observed image;
A simulated image coordinate data generation unit generates simulated image coordinate data indicating planar coordinates corresponding to pixels of the simulated image generated by the simulated image generation unit based on the elevation data stored in the elevation data storage unit. Simulated image coordinate data generation processing generated using a CPU;
The observed image coordinate data generation unit is indicated by the simulated image pixel corresponding to the pixel of the observed image specified by the corresponding pixel specifying unit and the simulated image coordinate data generated by the simulated image coordinate data generating unit. Observation image coordinate data generation processing for generating observation image coordinate data indicating a plane coordinate corresponding to the pixel of the observation image using a CPU based on the plane coordinate corresponding to the pixel of the simulated image;
The observed image coordinate data generated by the observed image coordinate data generating unit, wherein the corrected image generating unit generates an image in which the pixels of the observed image stored in the observed image storage unit are arranged at positions corresponding to plane coordinates. An observation image correction program that causes a computer to execute correction image generation processing that is generated using a CPU as a correction image based on the above. The observation according to claim 6, wherein the simulated image generation unit generates a fore-shortened image that causes a high altitude to fall down on an observation radar side that has performed radar observation and shows the simulated image as the simulated image. Image correction program. The simulated image generation unit calculates three-dimensional coordinates of an observation radar that has performed radar observation based on the observation condition information, and each lattice point of the ground surface indicated by the calculated three-dimensional coordinates of the observation radar and the elevation data The distance from the observation radar to each grid point on the ground surface based on the plane coordinates of the surface and the altitude of each grid point on the ground surface indicated by the elevation data and at each grid point on the ground surface formed by the electromagnetic wave emitted by the observation radar The incident angle is calculated, the intensity of the reflected wave from each lattice point on the ground surface is calculated based on the calculated incident angle, and the intensity calculated for the pixel at the position in the image corresponding to the calculated distance The observation image correction program according to claim 6, wherein the simulated image is generated with a shadow corresponding to the image. The corresponding pixel specifying unit specifies two pixels of the simulated image corresponding to two pixels of the observation image, and each pixel position of the two pixels of the observation image and each pixel position of the two pixels of the simulation image At least one of the observed image and the simulated image is affine transformed based on the amount of misalignment, and the pixel of the simulated image at the same pixel position as the pixel of the observed image after affine transformation is converted to the pixel of the observed image. The observation image correction program according to claim 6, wherein the observation image correction program is obtained as a pixel of the simulated image corresponding to.   The observation image correction program according to any one of claims 6 to 9, wherein the observation image is an optical image captured using an optical sensor. An observation image storage unit for storing an observation image indicating an image of the ground surface generated based on observation data acquired by radar observation using a storage device;
An observation condition storage unit for storing observation condition information indicating information on observation conditions of the radar observation using a storage device;
Using an altitude data storage unit that stores altitude data indicating the plane coordinates of each grid point of the ground surface divided by a grid and the altitude of each grid point using a storage device,
A simulated image generation unit uses a CPU (Central Processing Unit) to perform radar observation based on the observation condition information stored in the observation condition storage unit and the elevation data stored in the elevation data storage unit. Simulate and perform a simulated image generation process to generate a simulated image showing the image of the ground surface based on simulated data acquired by simulated radar observation,
The corresponding pixel specifying unit uses a CPU to generate a plurality of pixels constituting the observation image stored in the observation image storage unit and a plurality of pixels constituting the simulation image generated by the simulation image generation unit. Performing the corresponding pixel specifying process for specifying the pixel of the simulated image corresponding to the pixel of the observed image,
A simulated image coordinate data generation unit generates simulated image coordinate data indicating planar coordinates corresponding to pixels of the simulated image generated by the simulated image generation unit based on the elevation data stored in the elevation data storage unit. Perform the simulated image coordinate data generation process generated using the CPU,
The observed image coordinate data generation unit is indicated by the simulated image pixel corresponding to the pixel of the observed image specified by the corresponding pixel specifying unit and the simulated image coordinate data generated by the simulated image coordinate data generating unit. Performing observation image coordinate data generation processing using a CPU to generate observation image coordinate data indicating the plane coordinates corresponding to the pixels of the observation image based on the plane coordinates corresponding to the pixels of the simulated image;
The observed image coordinate data generated by the observed image coordinate data generating unit, wherein the corrected image generating unit generates an image in which the pixels of the observed image stored in the observed image storage unit are arranged at positions corresponding to plane coordinates. An observation image correction method comprising: performing a correction image generation process using a CPU as a correction image based on the above.